A U4008 abend means that the required load module RHDCCODE cannot be found.
Since r18.0, this module has been located in the CUSTOM.LOADLIB. Due to the re-structuring of the CA-IDMS loadlibs since r18.0, it can be a common problem that CUSTOM.LOADLIB has been left out of STEPLIB.
To resolve the problem, add CUSTOM.LOADLIB to STEPLIB.